1. Field of the Invention
The invention relates to a voltage-controlled device for a central processing unit (CPU), particularly to a voltage-controlled device, method and computer device capable of dynamically regulating voltage and effectively saving energy.
2. Description of Related Art
Under the situation that the warm-room effect is getting severely, most countries are devoted to working out solutions to deal with such a problem. Among which, an effective and direct approach is to save energy. In the PC industry, a CPU plays an important role. The powerful operating ability thereof brings into progressive modernization of the science and technology, while consumption of the power of the CPU is a concerned object.
In the PC, the core voltage required by the CPU is determined by a voltage identification (VID) generated according to working modes of the CPU. FIG. 1A is a block diagram showing how to supply a core voltage to a CPU 11 in a conventional PC. The magnitude of the core voltage required by the CPU 11 is not the same each time. For example, as the CPU 11 is entering a power-saving mode, the core voltage required by the CPU is lower than that in a normal operating mode. Therefore, the CPU 11 will produce a VID according to the required operating voltage. In FIG. 1A, after being generated by the CPU 11, the VID is output to a voltage regulator module (VRM) 12. And then, the voltage regulator module 12 will determine the magnitude of the core voltage supplied to the CPU 11 according to the VID.
In addition, a CPU supplier, such as Intel Co., has defined an equation named a load line with respect to the voltage and current of a CPU. For example, FIG. 1B shows a load line with the load current and the core voltage respectively on X and Y axes of the plane. The coverage of the load line is that as the current of the CPU 11 varies, the voltage regulator module 12 has to change the corresponding voltage. Another key point of the load line is that as the CPU 11 is operated in a heavy load, the voltage thereof cannot be lower than a minimum voltage. Otherwise, the stability of the system cannot be assured. The previous approach of supplying the core voltage to the CPU 11 according to the VID, such as reducing or increasing the CPU voltage to proceed with energy-saving or to increase the performance of the CPU, cannot reach the step of automatically adjusting the fitted CPU voltage according to the load of the CPU, such that a user himself has to manually set a reduced or increased CPU voltage. However, a normal system cannot always be in the situation of a light load or heavy load, such that it cannot take care of the CPU simultaneously for both saving energy and increasing performance. For example, as the user wishes to increase the performance of the system, he manually sets a over-voltage for the CPU. However, when in an idle situation, such an increased CPU voltage is useless. As such, not only electric energy is wasted, but also heat-dissipating is becoming poorer.